Frankly, Zatara is a bit of a stock character. There were quite a few tuxedoed magician heroes running around during the golden age, even more if you include characters that wore turbans instead of top hats. If pressed, I'd guess that the very first was Mandrake the Magician (a character from a syndicated comic strip by the legendary Lee Falk before he created the Phantom), but there might be an earlier one.

In any case, the thing that makes Zatara stand out is the fact that he was part of the origin of his daughter Zatanna, who is arguably the highest profile magic user in the entire DC Universe.

He was also one of Bruce Wayne's many teachers, and I tried to play that up in his story a little bit by making him a friend of Thomas Wayne.